Conventional sneakers with air cushions generally have a definitely shaped air cushion disposed in a heel of a sneaker. Some sneakers have an air cushion formed in a sneaker to provide an anti-shock effect. The air cushion cannot be too thick, so the height of the air filled in the cushion is also comparatively low, with the practical shock-absorbing effect being small. An air cushion disposed in a heel can have a larger space so that it has comparatively large shock-absorbing dimensions. However, an air cushion often breaks, so a sneaker has to be discarded owing to the broken air cushion, and to date no sneakers have a structure for replacing an air cushion with a new one, resulting in waste.